Validation of Otoliths for Estimating Ages of Largemouth Bass to 16 Years

Abstract

The use of transverse sections of sagittal otoliths has been validated for estimating the ages of largemouth bass Micropterus salmoides to age 5. However, previous research has indicated that the accuracy of this method is low for fish older than age 5. We used known-age fish of ages 0-16 to confirm that the use of otoliths is valid for estimating the ages of older largemouth bass. The estimated ages were correct for 97% of the fish. We concluded that past difficulties with using otoliths were more likely the result of preparation and reader error than of the structures depicting incorrect ages. The preparation method used in this study was simpler and faster than conventional methods of preparing thin sections and therefore should yield results that are more consistent.

Validation of otolith ages for walleye (Sander vitreus) in the Winnebago System

“…While otolith age estimates have been validated for a number of other fish species including freshwater drum Aplodinotus grunniens (DavisFoust et al, 2009), lake sturgeon Acipenser fulvescens , striped bass Morone saxatilis (Secor et al, 1995), and largemouth bass Micropterus salmoides (Taubert and Tranquilli, 1982;Buckmeier and Howells, 2003), we failed to find any studies from the peer-reviewed literature that examined the accuracy of walleye age estimates derived from otoliths, or any aging structure, using known-age fish from a wide range of walleye age classes. Erickson (1983) assessed the accuracy of walleye age estimates derived from scales and otoliths from 100 known-age fish from a single age-3 year class, whereas Heidinger and Clodfelter (1987) investigated the accuracy of various aging structures from 0 to 4 year old knownage walleye.…”

“…While these studies made valuable contributions to the fisheries literature and expanded the understanding of the accuracy of walleye age estimates, they did not examine a wide range of walleye age groups and thus do not meet the standards required to approach full age validation (Campana, 2001). Validation of age estimates from all age groups is necessary for assessing age group bias and the impacts that aging error can have on management decisions (Buckmeier and Howells, 2003). Maceina (1997) proposed using residuals from catch curves as a potential recruitment index.…”

Precision and Bias of using Opercles as Compared to Otoliths, Dorsal Spines, and Scales to Estimate Ages of Largemouth and Smallmouth Bass

“…Opercles were stored in 70% ethyl alcohol for several days until they were processed; post-processed opercles were stored dry. We removed otoliths from the fish following standard procedures and stored them dry in coin envelopes (Buckmeier and Howells 2003).…”

“…Spines were viewed with transmitted light at 200x magnification under a Leitz-Wetzler compound microscope. We sliced otoliths in half through the focus using the Buehler Isomet saw, lightly burned the otolith, mounted the samples in clay with the cut surface parallel to the clay base, submerged them in water, and viewed them under the dissecting microscope (Buckmeier and Howells 2003). We boiled opercles for ~30 seconds, scrubbed them briefly with a wire brush to remove excess flesh and scales, then viewed them with the naked eye to count annuli.…”

Relations between hydrological variables and year-class strength of sportfish in eight Florida waterbodies

“…Age and growth for all species was determined from annuli on the sagittal otoliths (Taubert & Tranquilli, 1982;Hoyer et al, 1985;Maceina & Betsill, 1987;Crawford et al, 1989;Schramm, 1989;Hales & Belk, 1992;Buckmeier & Howells, 2003). The annuli on otoliths from all fish were counted by observing the whole otolith under a microscope.…”